PL PACKET 09191995 - Laserfiche WebLink

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CHAPTER 4 TRANSPORTATION 71 The forecasted year 2000 average daily traffic developed through the above described procedures are shown on Map 9. Actual 1986 traffic counts are shown on Map 8. It should be mentioned that the forecasted traffic volumes were assigned to the road network assuming unimpeded flow capacity. In reality as one travel route approaches congestion, drivers begin to use alternate routes which may be less direct. In other words, shifting of some of the traffic from one route to alternate routes will occur if the desired route lacks adequate capacity. This is an important factor which must be considered in interpreting the forecasted volumes. TRAFFIC CARRYING CAPACITY Once the quantity of travel demand for the year 2000 has been determined the roadway system must be evaluated to determine its ability to handle the forecast travel demand, not only in terms of quantity, but also in terms of service afforded. Quality of service is apparent to the road user in terms of his freedom to follow a path and speed of his own choosing, the ease, and the physical and mental comfort of his driving task. Quality of service also affects his safety, convenience and vehicle operating costs. "Level of Service" is a term devised by traffic experts to provide a qualitative measure of traffic related to various volume (quantity) conditions. "Level of Service" is identified by letter designations A through P to of increasing travel demand and decreasing quality of service. Levels of service are defined for two basically different operating conditions: Uninterrupted traffic flow as experienced on freeways and rural highways without traffic signals or STOP signs. Interrupted flow as experienced on urban arterials where the controlling factor is the ability of signalized intersections to handle travel demand. 1. Uninterrupted Flow — Level of service A through F for uninterrupted flow is defined as follows: Level of service A is the highest quality. It is a condition of free flow in which there is little or no restriction on speed or maneuverability. Level of service B is stable flow, but operating speeds may be affected by the presence of other traffic.